A camera module for use in a camera-equipped mobile phone, a digital camera, a security camera, or the like is structured such that a solid state image pickup element such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor), a wiring substrate including a glass substrate and a terminal, a sensor cover retaining the solid state image pickup element and the wiring substrate, a lens, and a lens holder are integrated.
An example structure of such a camera module is illustrated in FIG. 13. As shown in FIG. 13, a camera module 100 includes: a lens unit 120 consisting of a lens 121 and a lens holder 122; and an image pickup package 110 in which a solid state image pickup element 113 is placed in an internal space 118 surrounded by a glass substrate 117, a sensor cover 114, and a wiring substrate 111.
In a case of the camera module 100 having the above structure, ideally, any foreign matters do not enter the internal space 118 of the image pickup package 110 because, when foreign matters are attached onto the solid state image pickup element 113, a captured image is deteriorated. However, in a case where the internal space 118 is airtight completely in order to prevent entry of foreign matters, gas in the internal space 118 thermally expands due to a rise in temperature, which results in a risk of breakage from a joint section. Further, gas and ions are generated from adhesives 112 and 116 etc. due to change in temperature or in atmospheric pressure, which steams up the glass substrate 117.
In order to solve the above problem, for example, in a solid state image pickup element 200 disclosed in Patent Literature 1, as shown in FIG. 14, an adhesive layer 219 is provided on an inside wall of an image pickup package 210, thereby preventing foreign matters from attaching onto a solid state image pickup element 213. Further, a through hole 211a connecting inside of the image pickup package 210 with an outside thereof is provided in a wiring substrate 211 placed directly under the solid state image pickup element 213, so that open air is circulated and gas and ions generated from the adhesive layer 219 due to change in temperature or in atmospheric pressure are released.
For example, as shown in (a) of FIG. 15, (b) of FIG. 15, and (c) of FIG. 15, Patent Literature 2 proposes an image sensor unit 300 having such a structure that a ventilation section for allowing an inside of the image pickup package 310 to communicate with an outside thereof is provided on a flat surface of a sensor cover 314. In the image sensor unit 300, when the sensor cover 314 and a glass substrate 317 are adhered to each other, a ventilation section V for allowing an internal space 318 to communicate with the outside is provided by providing a region to which an adhesive 316 is not applied. Further, because an opening section of the ventilation section V inside the image pickup package 310 is provided outside a region facing a light-receiving surface of an image pickup element 313, foreign matters entering the internal space 318 of the image pickup package 310 through the ventilation section V are difficult to fall and be attached onto the light-receiving surface.